The Optical Imaging Core of the Washington University Center for Translational Neuroscience (WUCTN) will allow members of the Neuroscience community to expand already successful projects and initiate new projects, especially in the area of bioluminescence. While there are presently a variety of optical imaging facilities within the medical center and main campus, these have not been available to the larger neuroscience community because they have only limited technical support. To accomplish its goals, the Core will coordinate already existing resources at Washington University for confocal and two-photon microscopy by neuroscientists and also establish new low-light level imaging capabilities. Access to the Optical Imaging Core Facilities will be extended to Washington University neuroscientists at three separate locations. Two facilities will be housed at the Medical Campus (WUMS) and one at the Undergraduate campus (WU). All three facilities will offer instruction and supervision for the different microscopy methods supported. The Optical Imaging Core will offer facilities for: 1. Confocal microscopy for high resolution imaging of fluorescent probes. This includes the imaging and differentiation of variants of GFP (such as YFP, CFP, eGFP), and more red-shifted dyes (Cy5) in both living and fixed preparations. 2. Two-photon microscopy for deep tissue imaging, including in vivo and in vitro time-series measures. Use of the 2-photon technique will minimize damage due to repeated imaging. 3. Low-light imaging of fluorescent and bioluminescent reporters. This includes real-time imaging of gene activity using luciferase constructs and of other cellular events using novel transgenic reporters in cultured cells, in tissue slices and in whole small animals. 4. Technical support for the neuroscientists to ensure the efficient creation of high quality images for quantitative image analysis and ultimately publication. This includes training, education, software development, data management and maintenance of imaging equipment and materials. 22 of the 54 projects described involve clinically-relevant studies, and most of the others address hypotheses that directly inform translational research. Significantly several projects involve new experimental directions and collaborations that will be enabled and facilitated by access to these Core facilities.